Charles disstof



n @attenta-tes @anni ffies,

ePIARLEs'DIssToN', `or PHILADELPHIA, PENNSYLVANIA, AssIeNoE To HENRYr DIssroN, or SAME PLAGE.

Leners Patent Nb. 80,929, ma August 11, 186s.

IMPROVEMENT IN 'SAWS.

TO`-ALLA-WHOMUIT MAY CONCERN;

Be it knownthat .1, CHARLES -DIssToN, of Philadelphia, Pennsylvania, have invented an Improvement in Securing Detachable Teeth to Saw-Blades; and I do hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to that class ofv detachable saw-teeth which have circular bases adapted to circular recesses in the' blade; and my invention consists in making the base ofthe tooth and the recess therefor of the same diameter, in the first. instance, and in formingon the edge of the base, or on the edge of the recess, a fprotubcranee, as described hereafter, so that the tooth cannot be moved back to its place without'being forcibly driven, and so that it may be held so tightly .in itsplace that -its dislodgment is` prevented, without the aid of fastening-appliances.

vIn order to enable others skilled in the art to make and apply my invention, I will now proceed to describe the mode of carrying the same into effect, reference being had to the accompanying drawing, which forms a part ofV this specification, and in which- Figure l represents the tooth detached from the blade.

Figure 2, the recess in the blade for the reception of the tooth.

Figure 3 illustrates the mode of introducing the tooth to its place; and

- Figure 4 the tooth as it appearswhen fitted to its place.

Similar letters refer to,simila r parts throughout the several views,

Although'the tooth may be classed with what are known as teeth with circular bases, the edge of the base, a, does not coincide throughout with a true circle, as will be seen on examining the red line z, iig. 1, beyond which line the base of the tdoth has arprotuberanoe near y( The base may, in the rst instance, be lmade to coincide with a. true circle, and' the desired protirberance may be obtained by forcing the portion a'. of the base away, in` the direction of the arrow, fig. 1, from the body, a, of the base. This can be readily accomplished by striking the tooth, while it rests with one face on an anvil, several blows with a. hammer at the points n n 'n on theropposite face.

Thc'edge'ef the recess b, however, made in thc blade for the reception of the tooth, coincides with a true' circle of' the same diameter as that which defines the greater portion of the edge of the base, and on the edge of this recess and on the shoulder d, fig. 2, is formed a V-shaped rib, adapted toa similarly-shaped groove in the 'edge of thebase, d, a'nd that of the shoulder e of the tooth.

A portion,f, of thev edge of therecess b is cutaway foi" the reception of the protnberant portion y of the base of the tooth, the edge of which is also cut away atf to receive the projecting portion h of the edge of the recess b of the blade, when the tooth is adjusted to the position shown in fig. 3.

After the base of the tooth, while occupying this position, has been introduced into the recess, it is forced back in the direction of the arrow, iig. 3, when the protuberant portion y will' move upwards in contactl with the portion m of the edge of the recess. As the latter `is circular, however, and the portion y of the tooth projects beyond the circumference of a' circle of the same diameter as the recess, the tooth cannot be mbved back withoutbeing forcibly driven, and without the yielding ofthe portion a of the base. I

' When the tooth has been driven so far back that its shoulder e is in contact with the shoulder d of the blade, the base is vso tight'in' its place that no fasteningapplianees other than those described are necessary to prevent its dislodgment. l

In fastening teeth with circular bases to recesses Ain the blade of a saw, it has been usual to malte` the base of each toothlargcr iudiameter than the recess, and toicontract the tooth4 as it is being introduced intel its place, but this plan is objectionable, as n bas'e of larger diameter, when contracted for insertion into a recess of smaller diameter, cannot iit accurately to the latter.

In striking the tooth at the points it n, for the purpose of obtaining the protuberance y, the edge i of the base, from aboutthe point q to the point t, in the direction of the arrow 2, g.- 1, must' of necessity 'depart from a true circle, but from the point q, in a. contrary direction to the point w, the edge of4 the base is n-a true circle, of the sume diameter as the recess, to tvhich. it must consequently lit accurately, and against which the i base must be tightly forced durng'the act of driving back the tooth.

The base of the tooth may be made in a true circle, and the edge of the recess may be made to project at v, as' shown -by red lines, g. 3,`with a result the same as that described'above, but I prefer to make the recess in o. true circle throughout, andthe tooth-t'project at y.

I wish it to. be understood that I do no'tdesre to claim broadly a. detachable tooth with` a circular base adapted to a circular recess in the blade; nor do claim a rear projection' on the-'tooth for bearing against a.

shoulder-lon the edge of the, blade; but .Y

I claim as my invention, and desireto secure by Letters Patent- A detachable sawtooth, having a. circular elastic base,a.daptedfto a. circular recess in the blade, when there is on theedge of the said base or said recess, and from the circular line which defines the same, such aprojecton l,or protuberance that the elastic base will yield on 'fitting the tooth te its base,all as-herein set forth for the purpose speced. l v l f In testimony whereof,l have signed my name to this specieation in the presenceof two subscribingwtnesses.

' CHARLES DISSTON.

-Wtnesses ANDREW, RIDDEL, C. B. PRICE. Y 

